Hay ho all
Just having a brain fart
Is it possible to fit VN EFI heads to a 253
Or am i going to have to buy a 308 block
Thanks in advance
Efi head conversion
Started by
_the_new_a9x_replica_
, Jul 12 2007 01:04 PM
13 replies to this topic
#2
_pepperjack_
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Posted 12 July 2007 - 01:33 PM
yep you can fit VN EFI heads on 253 but why would you?
EFI heads have bigger ports the 253 wont suck as hard as 308 so the intake charge or velocity will be slow and it will be a slug with no go! thats why its not wise to put bigger valves in 253's same deal
EFI heads have bigger ports the 253 wont suck as hard as 308 so the intake charge or velocity will be slow and it will be a slug with no go! thats why its not wise to put bigger valves in 253's same deal
#3
_the_new_a9x_replica_
_the_new_a9x_replica_
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Posted 14 July 2007 - 08:33 AM
Thanks for that i didnt even think about that
But they do fit
well there you go i didnt think they would because the bore diameter would be smaller than a 308
But as normal i am wrong again
But they do fit
well there you go i didnt think they would because the bore diameter would be smaller than a 308
But as normal i am wrong again
#4
micklx
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Posted 14 July 2007 - 09:07 AM
In my experience, a 253 with a decent cam, inlet and exhaust will benefit from bigger valves. While they are not restricted by the old heads to the same extent that a 308 is, if you are looking for HP you will need bigger valves sooner or later.
Chances are you will upgrade to a 308 down the track any way ??? You are just wanting to do the conversion with the engine you already have for now.
Someone on these forums has a 253 with efi, I can't remember who it is, hopefully he will see this and can give you his first hand experience.
Chances are you will upgrade to a 308 down the track any way ??? You are just wanting to do the conversion with the engine you already have for now.
Someone on these forums has a 253 with efi, I can't remember who it is, hopefully he will see this and can give you his first hand experience.
#5
_Herne_
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Posted 14 July 2007 - 10:32 AM
I have the 253 with EFI, it generates more rear wheel Kw than a stock 253 but is not up to 308 figures. Still worth doing IMHO. Mine produced around 145 or so BHP from memory.
One thing you will need if going injection is to get the ecu reprogrammed, preferably whilst on a dyne to burn in a chip at the correct settings.
I do wish I had gone carby though and run it with a Torque Power inlet manifold and a wild cam
Hope that helps, dont mind chatting to you about it if you need help.
Cheers
Herne
One thing you will need if going injection is to get the ecu reprogrammed, preferably whilst on a dyne to burn in a chip at the correct settings.
I do wish I had gone carby though and run it with a Torque Power inlet manifold and a wild cam
Hope that helps, dont mind chatting to you about it if you need help.
Cheers
Herne
#6
_pepperjack_
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Posted 14 July 2007 - 02:01 PM
I wonder if there is anyone on this forum that the only mod they did was go to big valves on a 253 ? I did it in the early 80�s in a HQ it lost punch off the line and used more fuel !
Bigger is not always better! especially in a heavy street car
I have built 308�s with small valve heads that have easily out performed big valve engines of similar spec�s up to 4600 rpm, and lets face it most of us don�t rev our street cars much more than that, you can put a bigger cam in small valve engine and they sound and behave like they have a smaller cam - as compared to a big valve engine.
The higher the velocity of the intake and exhaust is, the quicker and more the cylinder is filled � the sweeter and crisp the engine will be, of course every thing is a compromise to have higher and greater rpm /hp you will have to go bigger .
Bigger is not always better! especially in a heavy street car
I have built 308�s with small valve heads that have easily out performed big valve engines of similar spec�s up to 4600 rpm, and lets face it most of us don�t rev our street cars much more than that, you can put a bigger cam in small valve engine and they sound and behave like they have a smaller cam - as compared to a big valve engine.
The higher the velocity of the intake and exhaust is, the quicker and more the cylinder is filled � the sweeter and crisp the engine will be, of course every thing is a compromise to have higher and greater rpm /hp you will have to go bigger .
#7
_Baronvonrort_
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Posted 14 July 2007 - 02:01 PM
Herne
How does the fuel economy compare with your EFI to pre conversion?
Can you do some testing and let us know what it currently gets?
How does the fuel economy compare with your EFI to pre conversion?
Can you do some testing and let us know what it currently gets?
#8
_Herne_
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Posted 14 July 2007 - 03:09 PM
Sorry I run a V8 and never worry about what it does to the gallon or what it costs me.
In short cant be bothered, never have and probably never will.
Cheers
Herne
In short cant be bothered, never have and probably never will.
Cheers
Herne
#9
_Herne_
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Posted 22 July 2007 - 02:11 PM
Latest update on my Dyno figures.I have the 253 with EFI, it generates more rear wheel Kw than a stock 253 but is not up to 308 figures. Still worth doing IMHO. Mine produced around 145 or so BHP from memory.
One thing you will need if going injection is to get the ecu reprogrammed, preferably whilst on a dyne to burn in a chip at the correct settings.
I do wish I had gone carby though and run it with a Torque Power inlet manifold and a wild cam
Hope that helps, dont mind chatting to you about it if you need help.
Cheers
Herne
yesterday I got 174.2 bhp at the rear wheels. Hardly sluggish performance...
Quote: EFI heads have bigger ports the 253 wont suck as hard as 308 so the intake charge or velocity will be slow and it will be a slug with no go! thats why its not wise to put bigger valves in 253's same deal: End quote
I beg to differ with the above quote to some degree, I guess it all depends what one is looking for! Certainly I could do with more torque and lower diff gears would help shift it off the line.
Your call
Cheers
Herne
#10
_redhotmike_
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Posted 22 July 2007 - 06:20 PM
Hi all,
I'm currently collecting parts to do a EFI conversion to a LX. I have most of it sussed (I think
but am yet to track down anybody who does extractors for the job. Anyways - I'm looking for a supplier for extractors that will preferably miss a knock sensor but still somehow fit into the LX. VN heads (probably) T5 box yadda yadda yadda....
I hope to blog the project over however long it takes and make a detailed "how to" resource for others to use. If there already is one - let me know - all help is greatfuly received.
Cheers,
Red Hot Mike
I'm currently collecting parts to do a EFI conversion to a LX. I have most of it sussed (I think
but am yet to track down anybody who does extractors for the job. Anyways - I'm looking for a supplier for extractors that will preferably miss a knock sensor but still somehow fit into the LX. VN heads (probably) T5 box yadda yadda yadda....I hope to blog the project over however long it takes and make a detailed "how to" resource for others to use. If there already is one - let me know - all help is greatfuly received.
Cheers,
Red Hot Mike
#11
_moot_
_moot_
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Posted 22 July 2007 - 07:35 PM
for the price of a 308/304 why would you bother....
#12
_moot_
_moot_
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Posted 22 July 2007 - 07:36 PM
pacemakerHi all,
I'm currently collecting parts to do a EFI conversion to a LX. I have most of it sussed (I think
#13
Neils LX
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Posted 26 July 2007 - 02:28 PM
Hi
If on a budget use factory VN extractors, drivers side goes staight in and passengers side only neads small work to fit. $700 pacemakers would be nice but thats also near a weeks wages
Chears Neil
If on a budget use factory VN extractors, drivers side goes staight in and passengers side only neads small work to fit. $700 pacemakers would be nice but thats also near a weeks wages
Chears Neil
#14
_Herne_
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Posted 26 July 2007 - 04:50 PM
To be different and try something.for the price of a 308/304 why would you bother....
Herne
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